In vehicle measurement, the flatness of the measuring station and an exactly horizontal alignment of the vehicle are very important in order to achieve accurate results during the measurement. For example, the manufacturers specify that the maximum difference in elevation between the wheel contact surfaces may not amount to more than 1 mm.
In addition, equal air pressures are required, at least in the wheels of one axle, in order to avoid an inclination of the body based on a different compression of the tires.
In order to obtain correct measuring results, it is therefore required to check both the flatness and the horizontal orientation of the measuring station, as well as the air pressure in the wheels of the vehicle to be measured before every measurement.
This checking takes up much time, so that there is a danger that the necessary verifications are dispensed with due to laziness, and, as a result, the vehicle measurement is carried out erroneously.